Stamp for thin sheet-metal plates, such as dental plates and the like



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FRIEDRICH HAUJRTMEYER, 0F ESSEN, GERMANY, ASSIG-NOR, 'LO FRIED. KRUIEP AKTIENGESEILSCHAFT, OI FSSEN-ON-THE-VRHR, GERMANY.'

STAMP FOR THIN SHEET-METAL PLATES, SUCIE AS DENTAL LATES AND THE LIKE.

Specification of Letters Patent.

Patenten nag. a, ieee.

.application filled February 14, 1921. Serial No. 444,989.

To all whom t may concern:

Be it known that I, Dr. FRIEDRICH HAUPT- MEYER, residing at Essen, Germany, a citizen of' the German Republic, have invented a certain new and useful Improvement in Stamps for 'Ihin Sheet-Metal Plates, such as Dental Platesk and the like (forfwhich I filed application in Germany on December 1, 1919), of which the following is a specification.

rIhis invention relates to stamps for thin sheet metal plates, such as dental plates and the like, and the object of the invention is to impart the desired form to such thin sheet metal plates in a single operation, Without any creases forming in the work, the formation of such creases being undesirable and to be avoided' even when the hardest material vis employed, e. g. steel, particularly that class of chromium-nickel steel which possesses a very high power of resistance to attack by acids. A

The invention as applied to the manufacture of dental plates willbe described with,

referencel to the diagrams in which-v Figure 1 is a central vertical section through the stamp, the blank andthe die, in the position lat the commencement of the stamping operation,

Figure 2 is a corresponding section during a period of the stamping operation and Figure nBris a corresponding` view in the position at the completionof the 'stamping operation. l

A denotes the die and B the sheet metal which forms the blank. The stamp C at the part which comes in contact with the blank is of a plastic substance, such as lead for.

example. This part of the stamp C is so formed that during the course of the Work the blank B is clamped as soon as possible at the upvs/ardly projecting edges a1 of the die between theV stamp and the die, as is shown in particular in Figure 2, the stamp being s'o formed that at t e commencement of the stamping eperation..`it is in contact with the blank B only between the edges o1 of the die A.

During the-course of the stamping operation the stamp adapts itself, owing to its plasticity, more and more to the orm of the die (see Figures 2 and 3) and the stamp becomes so altered inv shape during the stamping operation that before the completion of the stamping operation the blank B is firmly gripped between the stamp C and the edges L1 of the die A for the Ipurpose of preventing the formation of creases. At the same time the centre of the sheet metal B is gradually'pressed into the hollow part of the die. rIhe sheet metal B is thus drawn through inwards at the raised edges al of' the die 'A to correspond to the increasing requirement for material 'between 4the die and thestamp overcoming as it does so the grip produced by the pressure at the edges al of the die.

In comparison with known similar ar' rangements'the clamping of the `sheet metal H at the raised edges of the die whichy im- .parts the shape to the blank secures the ad `,vantage that thestamping can b'e carried out in a single operation without creases being formed in the blank, even when this latter consists of a material of' the greatest hardness and strength.

Claim.

A press for thin plates comprising in combination a concave die memberhaving a raised rim and a ductile stamp taperin towards its frontend and having on its ront end a cross-sectional -area smaller than'the area limited by said rim, said ductile stamp being adapted to'freely expand around its `whole circumference in lateral direction.

The Jforegoing specification si edat Essen, Germany, this 4th day o December, 

